The technique disclosed herein relates to a solid-state imaging device and an imaging apparatus.
In recent years, digital cameras etc. including built-in solid-state imaging devices have been widely used.
FIG. 16 is a diagram illustrating a configuration of a conventional solid-state imaging device. Referring to FIG. 16, a conventional solid-state imaging device 10 includes a pixel array 11, a row selector circuit (Vdec) 12, a column reader circuit (AFE) 13, a shutter mode adaptor 14, and a shutter mode switcher 15. Control lines (LRST, LTRG, LSEL) configured to drive pixel parts are connected between the row selector circuit 12 and the pixel array 11.
The pixel array 11 is formed of pixels arranged in rows and columns. In each of the pixels, a photodiode (PD) configured to perform photoelectric conversion, a floating diffusion (FD) configured to store a charge, a transfer transistor, a reset transistor, an amplifier transistor, etc. are provided.
The column reader circuit 13 receives, through signal output lines LSGN, data from each row of the pixels controlled to a readable state by the row selector circuit 12, and transfers such data to a signal processing circuit provided at a subsequent stage. The column reader circuit 13 includes, e.g., a correlated double sampling (CDS) circuit and an analog-to-digital converter (ADC).
A shutter mode switching signal SHRMODE output from the shutter mode switcher 15 is input to the row selector circuit 12. A resistor RVDD is provided between the row selector circuit 12 and a power supply VDD, and another resistor RVDD is provided between the row selector circuit 12 and ground VSS.
A rolling shutter method broadly employed for obtaining a moving picture and a global shutter method broadly employed for obtaining a still image have been known as exposure methods in solid-state imaging devices.
In the rolling shutter method, reset, exposure, and reading for pixels arranged in the same row are simultaneously performed. Exposure timing is different among the rows, resulting in occurrence of image distortion.
On the other hand, in the global shutter method, reset and exposure of all pixels are simultaneously performed. Thus, no image distortion occurs between adjacent ones of rows.
In the global shutter method, it is necessary to simultaneously perform exposure of all pixels. In, e.g., the case where the global shutter method is realized in combination with a liquid crystal shutter or a mechanical shutter, PDs of all pixels are reset with the shutter being opened. Such operation is called “all reset operation.”
After the lapse of a predetermined exposure time, the shutter is closed such that the PDs of the pixels are not exposed to light. In this way, exposure of all pixels is simultaneously performed.
Since the PDs of all pixels are simultaneously reset in the global shutter method, all reset signals RST are simultaneously switched. Reading in the global shutter method is similar to that of the rolling shutter method.
However, if the global shutter method is employed, it is necessary to simultaneously switch the potentials of all reset signals RST and transfer signals TRG (control signals for transfer transistors) (i.e., to perform the all reset operation). For such a reason, an excessive instantaneous current flows in the case of the global shutter method, and therefore there is a disadvantage that countermeasures against noise of a power supply is required. Moreover, if power supply capability is not sufficient, a latch-up is caused by an instantaneous change in voltage due to the instantaneous current, and, as a result, there is a possibility that the solid-state imaging device is damaged.
In the prior art, an impedance element (e.g., the resistor RVDD illustrated in FIG. 16) is, as the countermeasures against noise of the power supply, inserted between a pixel driver circuit and a power supply terminal thereof to reduce an excessive instantaneous current in the all reset operation.